The invention relates to a copy-guiding cylinder of a folder, which is operatable in different folding modes, and is disposed downline of a rotary printing machine.
The published German Patent Document DE 44 26 987 C2, which is exemplary of the prior art, discloses a folder with format changeover. The folder is equipped with at least two folding cylinders which are located downline of a cutting cylinder and of which at least one has at least two cylinder bodies which are mounted on a shaft, are positioned inside one another and, during standstill or operation, are adjustable relative to one another by a planetary-gear transmission. The first cylinder body cooperates with a cutting cylinder, while the second cylinder body cooperates with the at least one cylinder body of the second folding cylinder, it being possible for the second cylinder body to be adjusted together with the at least one cylinder body of the second folding cylinder.
The first cylinder body and the second cylinder body of the first folding cylinder are connected to one another via a first planetary-gear transmission and a second planetary-gear transmission, one shaft being common to both transmissions. The planetary gears of the first planetary-gear transmission are arranged rotatably on a driven gearwheel which drives the first cylinder body. The planetary gears drive a sun gear which is common to the two planetary-gear transmissions. The sun gear drives the second cylinder body via planetary gears of the second planetary-gear transmission, the two planetary-gear transmissions, in conjunction with one another, having a transmission ratio of 1:1.
The foregoing proposed construction involves a great mechanical outlay.
The French Patent 2 697 205 is concerned with a folder for processing continuous printed material webs. The folder described therein is equipped with a cutting device cooperating with a transfer cylinder that is driven about the axis thereof. The transfer cylinder, which is equipped with an interrupted circumferential surface, cooperates with a folding jaw cylinder having folding jaws on the circumference thereof, and sets of pins and folding blades are provided, which serve for transversely inserting copies severed from the material web into the folding jaws. Also provided on the transfer cylinder are devices by which relative displacement between pins and folding blades can take place. Closure plates are accommodated on the circumference of the transfer cylinder on both sides of the folding blades and, likewise, on both sides of the sets of pins. The two closure plates can be moved relative to one another in the manner of a coulisse or sliding block, the plates forming a virtually continuous outer lateral surface of the cylinder, regardless of the respective angular position of the folding blades and the sets of pins relative to one another on the circumference.
A disadvantage with this construction was that the curvature of the closure plates was difficult to produce and the coulisse-type guidance of the closing plates within one another inevitably resulted in a stepped lateral surface of the cylinder, although the step was relatively small. This results in different circumferential speeds for the copies on the circumference of a cylinder formed in this manner.
As a further development of the foregoing constructions of the prior art, the invention of the instant application has, as objects thereof, maintaining the cylindricity of a product-guiding folding cylinder that is adjustable in accordance with the then operating folding mode, and achieving a constant circumferential speed of the copies guided on the circumference of the cylinder.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, in a rotary printing machine, a folder operatable in different folding modes, and having a copy-guiding cylinder to which copies severed from a material web by a cutting-cylinder pair are feedable, the copy-guiding cylinder having a circumferential surface wherein gripping and cross-folding elements are accommodated, comprising a device including movable circumferential-surface parts guidable by a respective guide element and, during folding-mode changeovers, selectively extendable into the circumferential surface of the cylinder and retractable between stationary and movable segments of the copy-guiding cylinder which are positionable relative to one another.
In accordance with another feature of the invention, the circumferential-surface parts are pivotable about a pin carried by one of the segments of the cylinder.
In accordance with a further feature of the invention, the pin is carried by a stationary segment of the cylinder.
In accordance with an added feature of the invention, the respective guide element of the circumferential-surface parts is connected to one of the segments of the cylinder.
In accordance with an additional feature of the invention, the respective guide element is accommodated on a movable segment of the cylinder.
In accordance with yet another feature of the invention, the device includes a prestressing unit for subjecting the circumferential-surface parts to torsion, at respective mounting locations thereof.
In accordance with yet a further feature of the invention, the circumferential-surface parts are provided with a follower element guidable in the guide element.
In accordance with yet an added feature of the invention, the follower element is formed as a roller.
In accordance with yet an additional feature of the invention, the guide element has a cage bounded by two runner surfaces.
In accordance with still another feature of the invention, the runner surfaces merge into an upper and a lower cutout formed in the guide element.
In accordance with still a further feature of the invention, the device includes a toggle-lever system for supporting the movable circumferential-surface parts.
In accordance with still an added feature of the invention, the toggle-lever system includes a lever rotatably mounted on the stationary segment.
In accordance with still an additional feature of the invention, the device includes a stop formed between upper and lower levers of the toggle-lever system in vicinity of a toggle joint thereof.
In accordance with another feature of the invention, the device includes a prestressing element actable upon the toggle-lever system.
In accordance with a further feature of the invention, the segments of the cylinder have a spacing formed therebetween for allowing overfold corrections.
In accordance with an added feature of the invention, the folder in the rotary printing machine is pinless.
In accordance with a concomitant aspect of the invention, there is provided a copy-guiding cylinder for a folder of a rotary printing machine, the folder being operatable in different folding modes, the cylinder having copies severed from a material web by a cutting-cylinder pair feedable thereto, and having a circumferential surface wherein gripping and cross-folding elements are accommodated, comprising movable circumferential-surface parts guidable by a respective guide element and, during folding-mode changeovers, selectively extendable into the circumferential surface of the cylinder and retractable between stationary and movable segments of the cylinder which are positionable relative to one another.
The solution for the problems found in the prior art, which are realized in the invention of the instant application is accompanied by a large number of advantages. On the one hand, retraction and extension of the circumferential-surface parts take place automatically during folding-mode changeovers due to the positive guidance of the circumferential-surface parts. On the other hand, a precisely achievable cylindricity of the circumferential surface of the copy-guiding cylinder is assured by mounting the circumferential-surface parts on one of the segments of the copy-guiding cylinder. The circumferential-surface parts, which are retracted or extended with positive guidance during folding-mode changeovers, are adapted or matched with respect to curvature to the lateral surface of the cylinder, with the result that different speeds are not imposed upon copies guided on the lateral surface of the copy-guiding cylinder according to the invention.
In an advantageous development of the idea upon which the invention is based, the circumferential-surface parts can be pivoted about a pin on one of the segments of the copy-guiding cylinder. The movable circumferential-surface parts are preferably mounted on the stationary segment, while the guide elements guiding the circumferential-surface parts in accordance with a selection of the folding mode are preferably accommodated on the movable segment of the copy-guiding cylinder.
In order to allow the circumferential-surface parts to pivot about the mounting thereof with as little play as possible, the mountings of the circumferential-surface parts are provided with a prestressing unit which imposes a torsional moment thereon. The circumferential-surface parts themselves are provided with a follower element which is guided in the guide element and, depending upon the folding-mode changeover, produces a retraction or extension movement of the circumferential-surface part. The follower element may be rotatably formed on the circumferential-surface part, for example, as a runner roller or as a bearer ring. In order to achieve a precisely operating construction with as long a service life as possible, cages which enclose the follower elements and are bounded by two curved runner surfaces are formed on the guide element. The runner surfaces, respectively, merge at the upper and lower ends thereof, respectively, into an upper and a lower cutout or recess formed in the guide element. In the upper and lower cutouts of the guide element, the follower elements can be displaced in the circumferential direction so that it is possible to make overfold adaptations or adjustments of between 1 and 5 mm on the copy which is to be folded, without any retraction by a circumferential-surface part between the segments of the copy-guiding cylinder during the overfold-adaptation or adjustment operations.
The circumferential-surface parts are advantageously supported by a toggle-lever system. One of the levers of the toggle-lever system is mounted rotatably on the stationary segment of the copy-guiding cylinder. At the toggle joint thereof, the connecting location between the upper and the lower levers, the toggle-lever system is subjected to the action of a prestressing element, which avoids play and thus produces precise guidance of the mechanical components of the toggle-lever system. A stop may advantageously be formed on one of the levers of the toggle-lever system, the stop precisely defining the extended position of the circumferential-surface part and thus ensuring that the precise cylindricity of the circumferential surface of the copy-guiding cylinder is maintained when the circumferential-surface parts are extended.
Provided between the segments of the copy-guiding cylinder are spacings which, together with the upper and the lower cutouts provided in the guide elements, allow adaptation or adjustment of the overfold both in the double parallel-fold folding mode and in the delta-fold folding mode.
The copy-guiding cylinders may advantageously be used both in folders having sets of pins and in folders which operate without pins.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a copy-guiding cylinder of a folder, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: